Clinical Experiments with Electron Therapy up to 30 MeV

Abstract

For the last two years we have been using a Brown Boveri Betatron as a radiation source for electrons in the voltage range of 10 to 30 MeV; it belongs to the Radiological Department of the University and the Inselspital, Bern. I have the privilege of speaking to you about our early clinical experiments in the application of electron therapy as introduced here by Professor Zuppinger and carried out with my colleagues. We are aware that it is too early to draw a conclusive picture of the outlook and of all the possibilities in this relatively new field of radiotherapy. Nevertheless, early results from over 200 patients with neoplasms are so encouraging that we feel this may be a valuable new approach to tumour therapy. The betatron, built in 1953, is of an early type of construction and has a fixed tube and thus an immovable beam. The patient has to be placed according to the field chosen for irradiation. The same circular tube inside the machine makes it possible to emit either X rays or electrons up to 30 MeV. The electron beam leaves the tube in a slightly different direction, about 7 deg. more tangentially than the X-ray beam. For electron therapy, a frame of rectangular size is fixed on the aperture of the betatron; it contains a flat ionization chamber which measures the exit dose by integration. At the end of the frame, interchangeable discs are applied (composed of aluminium, brass and lead, 8 cm thick).